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Organic vegetable producers in Georgia, USA, utilize a range of amendments to supply nitrogen (N) for crop production. However, differences in soil type, fertilizers and environmental conditions can result in variability in N mineralization rates among commonly utilized organic fertilizers in the region. In this study, the effects of temperature on N mineralization from three commercial organic fertilizers [feather meal (FM), pelleted poultry litter (PPL) and a mixed organic fertilizer (MIX)] in two soil types from Georgia, USA (Cecil sandy clay loam and Tifton loamy sand) were evaluated for 120 d. Net N mineralization (Net Nmin) varied with soil type, fertilizer and temperature. After 120 d, Net Nmin from the FM fertilizer ranged between 41% and 77% of total organic N applied, the MIX fertilizer ranged between 26% and 59% and the PPL fertilizer ranged between 0% and 22% across all soil types and temperatures. Incubation at higher temperatures (20 °C and 30 °C) impacted Net Nmin of FM fertilizer in the Tifton series soil. Temperature and soil type had a relatively minor impact on the potentially mineralizable N of the PPL and MIX fertilizers after 120 d of incubation; however, both factors impacted the rate of fertilizer release shortly after application, which could impact the synchronicity of N availability and plant uptake. Temperature-related differences in the mineralization of organic fertilizers may not be large enough to influence a grower's decisions regarding N fertilizer inputs for vegetable crop production in the two soils. However, organic fertilizer source will likely play a significant role in N availability during the cropping season. [ABSTRACT FROM AUTHOR]

Shade nets can be an effective technology for producing bell pepper (Capsicum annuum L.) under hot climatic conditions. However, the effects of shading on fruit quality are still unclear. The objectives were to evaluate the effects of shade level on fruit mineral nutrient content, physiological disorders, and postharvest water loss. Trials were conducted in the spring–summer of 2016, 2017, and 2018 in Tifton, Georgia, USA, following a randomized complete block design with five shade levels: 0% (open field), 30%, 47%, 63%, and 80%. Shading increased the bell pepper fruit dimensions (length, diameter, and weight) in 2016 and mineral nutrient content in 2017. Fruit sunscald incidence decreased with increasing shade level, while blossom-end rot showed inconsistent responses. Postharvest fruit water loss and transpiration rates were highest in fruits from the unshaded treatment in 2016; there were no differences in fruit water loss among the shade levels. NONEXPRESSOR OF PATHOGENESIS-RELATED 1 (NPR1) and PATHOGENESIS-RELATED 1 (PR1) genes expressed more than 1.5-fold and 10-fold, respectively, at 47% shade level compared to 80%, though not significantly. Therefore, plants grown under shading had fruit with greater size, increased mineral nutrient content, and reduced sunscald incidence compared with the unshaded control. [ABSTRACT FROM AUTHOR]